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I suspect the problem is one or both of these two:
Are you sure you've got the right website? Flight NH805 is on All Nippon Airways (NH/ANA), not Japan Airlines (JL/JAL). There is also an ANA subsidiary called Air Japan, but AFAIK they don't fly to Bangkok and their flights are effectively indistinguishable from mainline ANA anyway.
Are you sure you've got ...

This should be no problem. Terminal 1-3 are connected via link bridges to Jewel so the only thing to consider is how early your check-in opens, this might be only 2 hours before the flight. If you are travelling from terminal 4, this will be harder, as you will have to take a bus there and back.
Alternatively, depending on your airline, you might be able to ...

Humans are fallible. Even the ones that are meant to be well trained.
I spent years in America on a visa that nobody recognised because there are so few in circulation (E3). I almost got arrested at a DMV because a police officer went on a power trip about me being in the country illegally because of the date on my Verizon bill being before my visa start ...